MADRID ― Upon Albert Einstein's death in 1955, the New York Times published a letter to the editor with a marvelous anecdote. Shortly after the atomic bombs had fallen on Hiroshima and Nagasaki, Einstein was asked, "Why is it that when the mind of man has stretched so far as to discover the structure of the atom we have been unable to devise the political means to keep the atom from destroying us?" His answer was timeless: "That is simple, my friend. It is because politics is more difficult than physics."As a former student of physics in East Germany, German Chancellor Angela Merkel was able to confirm the truth of Einstein's quip firsthand when she went into politics. I humbly believe that I can attest to the same, as my own life has followed a somewhat similar path. Just as I had done in Spain a few years before, Merkel reacted to the collapse of the dictatorship she lived in by leaving physics to embrace public service. Eventually, she got caught up in the whirlwind of European politics.In her various public roles, and throughout 13 years as chancellor, Merkel has always maintained a methodical and reflective style that suits her scientific background. But world politics seems to be diverging from that style, and increasing agitation in Germany has taken a toll on her standing.Last month, Merkel announced that she would not be seeking another term as chancellor, and that at the end of this year, she would step down as leader of the Christian Democratic Union (CDU). The race to replace her has already begun. Merkel's successors may well be worthy of filling her shoes, but there is no doubt that Germany and the rest of Europe will sorely miss her composure and steadiness.Much has been said about Merkel's achievements and failures. The greatest blot on her record may be the austerity policies that her government promoted in the European Union after the global financial crisis. Those policies increased inequality, deepened the divide between northern and southern member states, and slowed economic recovery. Since then, populists ― particularly the governing Five Star Movement/League coalition in Italy ― have seized on the painful legacy of austerity for their own political gain.Similarly, some blame Merkel for the rise of far-right parties, including the Alternative fur Deutschland (AfD) within Germany itself. After welcoming over one million refugees in 2015, Merkel became the bete noire of nationalist anti-immigrant forces across Europe. Needless to say, however, there is a stark contrast between her advocacy of austerity and her decisions at the height of the refugee crisis. In the latter case, Merkel put her own political future on the line to defend European solidarity at a time when other countries no longer seemed willing to do so.In a recent address to the European Parliament, Merkel once again stood up for the EU's foundational values. She joined French President Emmanuel Macron ― with whom she showed great rapport at the commemoration of the Armistice Day centennial in Paris ― in his call to form a European army. As both Macron and Merkel have made clear, such a force would not only be compatible with NATO; it would actually strengthen the organization. Predictably, however, Merkel's ambitious speech elicited scorn from Euroskeptics, who would much rather see the EU succumb to despair and political opportunism.In light of her announced departure, some already regard Merkel as a "lame duck" whose legacy will now be debated in political obituaries. Yet these eulogies are premature: There is good reason to believe that she is not yet done forging her European legacy.To be sure, Merkel's successor at the head of the CDU may not be closely aligned with her positions, and could inject more instability into the coalition government with the Christian Social Union (the CDU's Bavaria-based sister party) and the Social Democrats (SPD). But even under those circumstances, Merkel would have a few cards up her sleeve. For starters, a no-confidence vote in Germany cannot succeed unless an alternative candidate wins the backing of an absolute majority in the Bundestag. That has happened only once ― when Helmut Kohl of the CDU replaced Helmut Schmidt of the SPD as chancellor in 1982 ― and it would be extremely unlikely in a parliament that is as fragmented as the current Bundestag.A scenario in which Merkel finishes out her term, staying on for another three years, should therefore not be ruled out. She remains very popular on the international scene.And, liberated from electoral pressures, at least of a kind focusing on her directly, she may feel freer to pursue a more proactive foreign policy. Recall that it was during his final years in office that U.S. President Barack Obama achieved some of his biggest milestones in foreign policy. In addition to restoring diplomatic relations with Cuba, the Obama administration concluded the nuclear deal with Iran and signed the Paris climate agreement. Though President Donald Trump has sought to reverse these accomplishments, he has not been able to consign them to history.For the EU, it would be healthy if Merkel were to continue revitalizing the Franco-German axis, thereby opening the door to EU-level reform. Nevertheless, there are significant obstacles ahead. In this day and age, it is abundantly clear that politics is more difficult than physics. However, we would do well not to underestimate Merkel, and to heed another timeless Einstein quote: "In the middle of difficulty lies opportunity."

Javier Solana is a distinguished fellow at the Brookings Institution and president of ESADEgeo, the ESADE Center of World Economy and Geopolitics. Copyright belongs to Project Syndicate (www.project-syndicate.org)